Motor disorders in DSM-5 include three conditions: developmental coordination disorder (DCD), stereotypic movement disorder, and tic disorders (Tourette syndrome covered in OCD spectrum stage). Each represents a different pattern of disordered movement during the developmental period.
Developmental coordination disorder (DCD) involves significantly impaired motor coordination that interferes with daily activities and academic achievement. Affects 5-6% of school-age children. The child is "clumsy" in ways that go beyond typical variation — frequent tripping, dropping objects, illegible handwriting, difficulty with utensils, difficulty learning to ride a bike, athletic struggles, slow performance of motor tasks compared to peers.
Impact of DCD extends beyond motor function. Children with DCD often have lower physical activity (limiting cardiovascular fitness and social participation), reduced self-esteem, increased risk of anxiety and depression, academic difficulties (handwriting affects all written work), and social challenges (sports are often a social organizing activity for children). Often co-occurs with ADHD, dyslexia, autism.
DCD treatment centers on occupational therapy with task-specific motor learning approaches. Cognitive Orientation to Daily Occupational Performance (CO-OP) is an evidence-based approach in which the child develops cognitive strategies to break motor tasks into manageable components. Earlier intervention produces better outcomes. School-based OT services often the primary access point.
Stereotypic movement disorder involves repetitive, seemingly driven, non-functional motor behaviors that interfere with activities or produce self-injury. Common stereotypies: rocking, head-banging, hand-flapping, body-rocking, self-biting, hand-mouthing. Some are self-soothing; some appear sensory-seeking; severe cases include self-injurious behaviors.
Stereotypies vs tics: stereotypies are typically rhythmic, often sustained, frequently bilateral, often self-soothing. Tics are sudden, brief, often asymmetric, preceded by premonitory urges. Stereotypies often emerge in early childhood and may decrease or persist; tics typically emerge ages 4-7 with characteristic waxing-waning course. Different mechanisms, different treatments.
Stereotypies in different populations: common in intellectual disability and autism (where they often serve self-regulation or sensory functions); also occur in typically developing children (often more circumscribed, often outgrown). When severe and producing self-injury, intervention is appropriate; mild stereotypies in otherwise typical development may not require treatment.
Treatment of stereotypic movement disorder: behavioral interventions (habit reversal training adapted, addressing sensory regulation needs, environmental enrichment), parental coaching, sometimes pharmacotherapy for severe self-injurious behavior (atypical antipsychotics with caution). Address underlying anxiety or sensory regulation needs that drive the behavior.
When you encounter a child with substantial motor coordination difficulty or with concerning repetitive movements, structured evaluation matters. DCD responds to OT intervention. Severe stereotypies may respond to behavioral approaches. These disorders are real, identifiable, and treatable.